The sound comes first. A flat metallic slap from one side of the header, usually as the door is coming down, and then a rattle as something loose finds its way against the track. You look up and one cable is hanging in a loop instead of running tight from the drum to the bottom corner. The door still moves, more or less, which is what makes this so easy to keep using. The next cycle is the one that puts a cable in the wrong place and the door in the wrong plane, and by then you are looking at bent track and a twisted panel instead of a cable job.
With thousands of 5-star ratings across Google, Yelp, Facebook, and Thumbtack, Local Garage Doors runs cable off drum repairs across California, Nevada, and Arizona every week, and in nearly every case the cable did not fail — it was allowed to go slack, and slack is what let it leave the groove.
If a cable is off the drum right now, stop operating the door and read the next section first. For same-day service, call 
866-337-1631, 
email info@localgaragedoors.com, or schedule your appointment today.
Stop Cycling the Door
A cable that has left the drum is no longer sharing the load. The other cable is carrying the door alone, pulling from one corner of a panel assembly designed to be lifted from both. Every cycle from that point adds twist to the door and side load to the rollers.
Do not run the opener to “get it back on.” Pull the emergency release only if the door is fully closed and stays closed. If the door is partway up, leave it where it is and keep people and vehicles out from under it. A door hanging on one cable is a door hanging on one cable, and residential doors run 130 to 400 pounds and more.
Why the Cable Stays On in the First Place
Nothing clamps a lift cable into its groove. The cable sits in the spiral groove of the cable drum held there by one thing: tension. The weight of the door pulls down on the cable, the spring torque pulls up through the drum, and the cable is squeezed into the groove between those two forces.
Take the tension away and there is nothing holding it. The cable is free to lift out of the groove, ride over the flange, or slip down onto the shaft. That is the whole mechanism, and it means every cause of a jumped cable is really a cause of momentary slack.
Three things produce that slack: the door stops moving while the shaft keeps turning, the shaft geometry puts the cable at a bad angle, or something in the system has already shifted.
Cause One: The Door Stops and the Shaft Doesn’t
This is the most common origin by a wide margin, and it usually happens on the way down.
The opener drives the door closed. The door meets something — a bag of soil, a bike tire, a raised floor slab, ice at the threshold — and stops. The opener’s force setting is generous enough that it keeps driving for a beat before the safety reverse acts. The springs unwind through the drums the whole time. The door is not descending, so the cable coming off the drum has nowhere to go except into a loop.
Once the loop forms, the next open cycle winds that loop back on in the wrong place. Sometimes it seats. Often it climbs on top of the wrap below it, and the following cycle throws it clear.
Uneven floors do this quietly for years. So do doors that close to the floor and pop back up, because a down limit set too far past the floor drives the door into the slab and pays out cable it cannot use. So does an opener whose down force has been turned up to overcome a balance problem instead of fixing the balance problem.
Cause Two: The Shaft or Bracket Geometry Is Off
The cable should leave the drum on a straight line down to the bottom bracket, parallel to the track, with no sideways component at all. Anything that puts the cable at an angle to the groove makes it want to climb.
The shaft is not level. The torsion tube runs across the header on two end bearing plates and at least one center bearing plate. If one end plate has pulled out of the header, or the header has settled, the shaft tilts. Both drums tilt with it, and both cables now feed at an angle.
A bearing has worn. A worn bearing lets the shaft wander in its seat rather than spinning true. The cable feed angle changes slightly through every revolution, which is enough to work the cable toward the flange over hundreds of cycles.
The bottom bracket has shifted. The cable’s lower anchor point sets the line the cable follows. A loose, bent, or partly pulled bottom bracket moves that anchor inward or outward, and the cable is no longer feeding parallel to the drum face.
A drum has slipped on its setscrews. Cycle vibration and years of thermal expansion can loosen a setscrew. Once one drum creeps, the two cables no longer take up together — one goes slack while the other loads, and the slack one jumps. Slipped drums are also behind many cases of a door that closes unevenly and then auto-reverses.
Cause Three: The System Has Already Changed
Sometimes the jumped cable is the second failure, not the first.
A spring broke. On a two-spring system, one broken spring cuts available torque roughly in half. The door becomes heavy, the opener strains, and travel becomes jerky enough that cable tension fluctuates through the cycle. Slack appears at the top of travel where spring torque is lowest.
The door is out of balance. A door that is undersprung or oversprung never sits in equilibrium. An oversprung door lifts itself faster than the shaft is paying cable out, which produces slack at the drum directly. In a balanced door the springs do about 95% of the lifting and the opener the remaining 5%; when that split drifts, cable tension drifts with it.
The door is binding in the track. A door rubbing the frame, a bent vertical track, a seized roller, or a bowed bottom section all mean the door resists movement at some point in its travel. Wherever the door hesitates, the shaft keeps turning and slack appears.
A cable was replaced without the drums being re-seated. Cable length has to match. A cable an inch too long leaves a wrap of slack at the bottom of travel on that side, every single cycle, until it finds its way out of the groove.
What Fixing It Actually Involves
Rewinding a cable is not the repair. The repair is finding what created the slack, correcting that, and then re-seating both cables with the door weighed and balanced.
Spring tension comes off first. Both cables come off, both drums are checked for groove wear and correct indexing on the shaft, the shaft is checked for level and true, the bearings and bottom brackets are inspected, the door is checked for binding through its travel, and then the cables go back on with equal tension left and right. Cable replacement runs $150 to $300 depending on door size and cable length. If the underlying cause was a spring, replacement runs $250 to $850 depending on door size, spring quality, and whether it is a single- or two-spring system.
What does not work is winding the cable back on and turning the opener force up. That is the version of this repair that brings the door back to us with a bent track.
Regional Conditions Behind Slack Cable
Threshold ice and cold-stiffened springs around Truckee, South Lake Tahoe, Homewood, and Soda Springs. A quarter inch of ice at the bottom seal stops the door while the shaft keeps unwinding. Cold springs also deliver less torque on the first cycle of the morning, so the door hesitates on the way up and the slack forms at the top instead of the bottom.
Slab heave and settled headers in Sacramento, Woodland, Dixon, and Galt. Expansive valley soils move the slab and the frame independently. A floor that has risen a half inch under one side of the opening stops the door early on that side and pays out cable every close cycle.
Monsoon debris in Phoenix, Goodyear, Wickenburg, and Rainbow Valley. Blown grit and small debris collect at the threshold and under the seal. Combined with garage temperatures reaching 130°F, which softens lubricant and stiffens rubber seals, the door meets resistance at the floor it did not meet the week before.
Corrosion at the bottom bracket in Coronado, Oceanside, Vista, and Pacifica. Salt air attacks the bracket and its fasteners at the wettest point on the door. A corroded bracket that shifts under load changes the cable’s anchor line, and the cable starts working toward the drum flange.
Older Bay Area garages in Berkeley, Alameda, Oakland, and Martinez. Wood headers that have carried a door for fifty years give up fastener bite. An end bearing plate that has pulled a quarter inch out of the header is enough to tilt the shaft and change both cable feed angles.
The Bottom Line
Cables stay on their drums because tension holds them there. They come off when that tension disappears for even one moment, and something has to cause that moment.
Look for what stopped the door: an obstruction, an uneven floor, a down limit set too deep, a binding track, a broken spring, or a door out of balance. Look for what changed the cable’s line: a tilted shaft, a worn bearing, a shifted bottom bracket, a drum that crept on its setscrews.
If a cable is off right now, stop cycling the door. One cable carrying the whole door twists the panels and side-loads the rollers, and a $150 to $300 cable repair turns into panel and track work quickly. A spring and cable inspection or an annual lube and tune catches the slack before the cable finds its way out of the groove.
Call us at 866-337-1631,
email info@localgaragedoors.com.
🗓️Book an appointment online — same-day service available across California, Nevada, and Arizona.
Fully Licensed, CA #1023930 | NV #0087802 | AZ ROC #356696
Frequently Asked Questions About Cables Jumping the Drum
Can I put the cable back on the drum myself?
No. The drums are mounted to a shaft holding 200 to 300 foot-pounds of spring torque with the door closed. Re-seating a cable requires unwinding that tension with winding bars and securing the shaft first, and doing it with tension still in the springs is how people get hurt. It also does not address why the cable came off.
Why did only one cable come off?
Because slack forms on one side first. Whatever caused it — a floor that is higher on that side, a bottom bracket that shifted, a drum that crept — is local to that end of the door. The other cable stayed loaded and stayed seated. That asymmetry is the clue to the cause.
The door still opens. Do I need to fix it right away?
Yes. A door lifting on one cable puts a twisting load into panels that were built to be lifted at two corners, and it drives the rollers sideways into the track. Continuing to operate it is what turns a cable repair into a door off track repair with panel damage attached.
How much does it cost to fix a cable off the drum?
Cable replacement runs $150 to $300 depending on door size and cable length. If the cause was a broken or mismatched spring, spring replacement runs $250 to $850 depending on door size, spring quality, and system type. Our 2026 repair cost guide covers the full range of repairs.
Will turning down the opener’s force setting prevent this?
A correctly set down force helps, because it stops the opener from driving into an obstruction long enough to pay out cable. But force settings are a safety limit, not a fix for the underlying problem. If the door is binding or out of balance, the force setting is only masking it, and openers that fight an unbalanced door last 5 to 8 years instead of 12 to 20.
Does a jumped cable mean the cable has to be replaced?
Usually. A cable that has come off the groove has been crushed against the flange or the shaft, and it will show flattening or broken strands at that point. Cables are replaced in pairs so both have the same age and the same stretch. Reusing a cable that jumped is how the same door comes back in six months.
What maintenance actually prevents this?
An annual inspection that checks cable tension left and right, drum indexing, shaft level, bearing condition, bottom bracket security, and door balance. Most cable-off-drum calls we run had visible slack or visible drum wear months before the cable came off. Our Peace of Mind Protection Plan is built around catching that.